3-dB hybrids are used in high power RF circuits to realize a verity of components such as distributed loads, pulse compression systems, circulators, phase shifters, variable couplers, etc. Hence the synthesis of planner hybrids, with some times overmoded dimensions for use with ultra-high power applications have been the subject of interest for a long time. 3-dB hybrids are four port devices with a “matched” scattering matrix (diagonal elements are all zeros) representation that couples one port to the other two ports equally and the remaining port is isolated. This is true for all 4 ports. There are many realizations for this device.
What is needed is a 3-dB hybrid device for use in high power RF systems that are also compact and broadband.